Field of the Disclosure
The technology of the disclosure relates to machining of electrically-conductive workpieces. The machined electrically-conductive workpieces may be electrically-conductive shrouds or other electrically-conductive components used in various interconnect and electronics apparatuses, including printed circuit boards (PCBs).
Technical Background
Electrically-conductive workpieces are commonly used in manufactured products. A machining process can be performed to machine the electrically-conductive workpiece to the desired shape and size and having the desired geometric features. One method of machining electrically-conductive workpieces involves the use of conventional mechanical action machining techniques, such as grinding, turning, engraving, milling, and drilling. These conventional mechanical action machining techniques form the desired shape, sizes, and geometric features in the electrically-conductive workpieces by removing material using mechanical action.
An exemplary conventional machining process 10 employing mechanical action is illustrated in FIG. 1. As illustrated in FIG. 1, an electrically-conductive workpiece is machined to the desired size, shape, and/or geometric features (block 12). After machining, the workpiece may be cleaned to remove shavings and any other unwanted materials or debris from the machined workpiece (block 14). As a result of mechanical action machining, burrs may be formed in the workpiece. A burr is a raised edge or small piece of material attached to a workpiece after machining. Burrs are usually unwanted. Thus, after cleaning of the workpiece (block 14), the workpiece may be inspected for burrs (block 16). Inspection for burrs may be by means of human visual means or automated means, and may include the use of microscopes and other vision inspection machinery and apparatuses.
Burrs can cause numerous issues. For examples, burrs in drilled holes in machined workpieces can cause fastener and mechanical problems. Burrs can cause more stress to be concentrated at the edge of holes of machined workpieces, thereby decreasing resistance to fractures and shortening fatigue life. Burrs can also cause cracks by stress and strain on electrically-conductive workpieces that can result in material failure. Burrs may also trap cleaning and plating chemistry that increase the risk of mechanical and electrical failures. Burrs also increase the risk of corrosion, which may be due to variations in thickness of coatings placed on rougher surfaces to prevent corrosion. Further, sharp corners caused by burrs on electrically-conductive workpieces may concentrate electrical charge, thereby increasing static discharge and corrosion. If burrs are left to remain in moving parts, unwanted friction and heat can occur.
Because of the issues attributable to burrs, deburring is generally provided in a deburring process (block 18) to electrically-conductive workpieces after machining. Deburring involves the removal of burrs. Deburring can involve the application of mechanical, chemical, electrical, or any combination of these processes to workpieces. Deburring can also involve the application of abrasive cloths to workpieces, where the cloth is used to rub away burrs as well as polish the workpiece. In some cases, sanding of the workpiece may be necessary. Another common method of deburring is to physically pry or cut the burr from the surface using a sharpened instrument or tool. After deburring (block 18), the electrically-conductive workpiece can be cleaned (block 20) and a final inspection (block 22) performed to determine if burrs have been sufficiently removed from the machined workpiece. The final inspection (block 22) may involve the same inspection as block 16 in FIG. 1 or may involve a more rigorous inspection. If the machined workpiece does not pass final inspection (block 24), the deburring process can be repeated (blocks 16-20) with final re-inspection re-performed (block 22). Once the machined workpiece passes final inspection (block 24), the machining process 10 ends (block 26) with the resulting machined workpiece approved and ready for use in its intended application.
A deburring process, and particularly a hand deburring process, can add significant cost to an electrically-conductive workpiece. Deburring and inspection may take significant time and/or labor to perform. Further, some machined electrically-conductive workpieces may never pass final inspection and will have to be discarded. The hand deburring process may sufficiently remove burrs, but may cause the electrically-conductive workpiece to not be within other specifications, such as if material is worn away in certain locations more than other locations, or in a manner that causes tolerances of the electrically-conductive workpiece to not be within specifications.